Pneumatic random vibration generator

Abstract

A true random vibration generator for use in mechanical vibration generation includes a housing, a piston, and a programmer. The housing defines a cylinder closed at an impact end. The piston is slidably disposed in the cylinder and propelled by a pressurized gas. The programmer is freely moveable in the cylinder between the piston and the impact end of the cylinder. As the piston is propelled towards the impact end of the cylinder by the pressurized gas, the piston strikes the programmer causing the programmer to randomly bounce between the impact end of the cylinder and the piston. The bouncing continue until the programmer impacts the housing and the cylinder at substantially the same time. The piston is then propelled back its original position by the pressurized gas and the impact with the housing. The above described piston cycle is repeated and continues to impart vibration energy to the housing.

What is claimed is: 
     
       1. An apparatus for generating random vibration, comprising: a housing defining a bore closed at a first end;   a piston slidably disposed in said bore;   a programmer disposed in said bore between said piston and said first end of said bore, said programmer being freely movable between said piston and said first end; and   means for propelling said piston toward said first end of said bore causing said piston to strike said programmer and said programmer to strike said housing at said first end of said bore.   
     
     
       2. The apparatus of claim 1, wherein said bore, said piston and said programmer are substantially cylindrical. 
     
     
       3. The apparatus of claim 2, wherein a second end of said bore is closed by a cap. 
     
     
       4. The apparatus of claim 2, wherein said means for propelling comprises: pneumatic means for propelling said piston toward said first end of said bore.   
     
     
       5. The apparatus of claim 4, wherein said housing is closed at a second end and said pneumatic means comprises: a thrust port in said piston, said thrust port having a first opening on a side wall of said piston and a second opening at a rear end of said piston;   a reverse-thrust port in said piston, said reverse-thrust port having a first opening on a side wall of said piston and a second opening at a head end of said piston:   an inlet port in said housing, said inlet port being configured to receive said pressurized gas from an external source and to provide said pressurized gas to said first opening of said thrust port of said piston when said piston is adjacent to said second end of said bore, and provide said pressurized gas to said first opening of said reverse-thrust port of said piston when said piston is adjacent to said first end of said bore;   a first outlet port in said housing near said first end of said bore, said first outlet port configured to allow gas to escape as said piston moves toward said first end of said bore; and   a second outlet port in said housing near said second end of said bore, said second outlet port configured to allow gas to escape as said piston moves toward said second end of said bore.   
     
     
       6. The apparatus of claim 2, wherein said programmer is made from an impact resistant material. 
     
     
       7. The apparatus of claim 6, wherein said impact resistant material is a polymer. 
     
     
       8. An apparatus for generating random vibration, comprising: a housing defining a bore closed at a first end;   piston means for reciprocating within said bore;   programmer means, disposed in said bore between said piston means and said first end of said bore, for transmitting randomly applied impulsive energy from said piston means to said housing, said programmer means being freely movable between said piston means and said first end; and   means for propelling said piston means towards said programmer means.   
     
     
       9. The apparatus of claim 8, wherein said bore, said piston means and said programmer means are substantially cylindrical. 
     
     
       10. The apparatus of claim 9, wherein a second end of said bore is closed by a capping means. 
     
     
       11. The apparatus of claim 9, wherein means for propelling comprises: pneumatic means for propelling said piston toward said first end of said bore.   
     
     
       12. The apparatus of claim 11, wherein said housing is closed at a second end and said pneumatic means comprises: thrust port means for directing gas to the rear end of said piston;   reverse-thrust port means for directing gas to a head end of said piston;   inlet port means for receiving said pressurized gas from an external source and providing said pressurized gas to said thrust port means when said piston is adjacent to said second end of said bore, and provide said pressurized gas to said reverse-thrust port means when said piston is adjacent to said first end of said bore;   first outlet port means for allowing gas to escape from said bore as said piston moves toward said first end of said bore; and   second outlet port means for allowing gas to escape from said bore as said piston moves toward said second end of said bore.   
     
     
       13. The apparatus of claim 9, wherein said programmer is made from an impact resistant material. 
     
     
       14. The apparatus of claim 13, wherein said impact resistant material is a polymer. 
     
     
       15. A vibration table for randomly vibrating a component, comprising: a mounting plate configured to have the component mounted thereon;   means for generating vibration and imparting said vibration to said mounting plate, said means for generating vibration comprising: a housing defining a bore closed at a first end,   a piston slidably disposed in said bore,   a programmer disposed in said bore between said piston and said first end of said bore, said programmer being freely movable between said piston and said first end, and   means for propelling said piston toward said first end of said bore causing said piston to strike said programmer and said programmer to strike said housing at said first end of said bore.     
     
     
       16. The apparatus of claim 15, wherein said bore, said piston and said programmer are substantially cylindrical. 
     
     
       17. The apparatus of claim 16, wherein a second end of said bore is closed by a cap. 
     
     
       18. The apparatus of claim 16, wherein said means for propelling comprises: pneumatic means for propelling said piston toward said first end of said bore.   
     
     
       19. The apparatus of claim 18, wherein said housing is closed at a second end and said pneumatic means comprises: a thrust port in said piston, said thrust port having a first opening on a side wall of said piston and a second opening at a rear end of said piston;   a reverse-thrust port in said piston, said reverse-thrust port having a first opening on a side wall of said piston and a second opening at a head end of said piston;   an inlet port in said housing, said inlet port being configured to receive said pressurized gas from an external source and to provide said pressurized gas to said first opening of said thrust port of said piston when said piston is adjacent to said second end of said bore, and provide said pressurized gas to said first opening of said reverse-thrust port of said piston when said piston is adjacent to said first end of said bore;   a first outlet port in said housing near said first end of said bore, said first outlet port configured to allow gas to escape as said piston moves toward said first end of said bore; and   a second outlet port in said housing near said second end of said bore, said second outlet port configured to allow gas to escape as said piston moves toward said second end of said bore.   
     
     
       20. The apparatus of claim 16, wherein said programmer is made from an impact resistant material. 
     
     
       21. The apparatus of claim 20, wherein said impact resistant material is a polymer. 
     
     
       22. A random vibration generator for use in mechanical vibration applications, comprising: a housing defining a cylinder closed at a first end;   a piston slidably disposed in said cylinder;   a programmer disposed in said cylinder between said piston and said first end of said cylinder, said programmer being freely movable between said piston and said first end; and   means for propelling said piston toward said first end of said cylinder causing said piston to strike said programmer and said programmer to strike said housing at said first end of said cylinder.   
     
     
       23. The apparatus of claim 22, wherein a second end of said cylinder is closed by a cap. 
     
     
       24. The apparatus of claim 22, wherein said means for propelling comprises: pneumatic means for propelling said piston toward said first end of said cylinder.   
     
     
       25. The apparatus of claim 24, wherein said housing is closed at a second end and said pneumatic means comprises: a thrust port in said piston, said thrust port having a first opening on a side wall of said piston and a second opening at a rear end of said piston;   a reverse-thrust port in said piston, said reverse-thrust port having a first opening on a side wall of said piston and a second opening at a head end of said piston;   an inlet port in said housing, said inlet port being configured to receive said pressurized gas from an external source and to provide said pressurized gas to said first opening of said thrust port of said piston when said piston is adjacent to said second end of said bore, and provide said pressurized gas to said first opening of said reverse-thrust port of said piston when said piston is adjacent to said first end of said bore;   a first outlet port in said housing near said first end of said cylinder, said first outlet port configured to allow gas to escape as said piston moves toward said first end of said cylinder; and   a second outlet port in said housing near said second end of said cylinder, said second outlet port configured to allow gas to escape as said piston moves toward said second end of said cylinder.   
     
     
       26. The apparatus of claim 22, wherein said programmer is made from an impact resistant material. 
     
     
       27. The apparatus of claim 26, wherein said impact resistant material is a polymer.